以树皮为原料，合成了生物降解型聚氨酯泡沫材料，并考察了其作为化肥缓释的包膜材料对常用氮肥硫酸铵的控制释放性能。研究结果表明，以水作为发泡剂的多孔性聚氨酯包裹硫铵后，在模拟自然界雨淋的作用下，释放曲线大致呈抛物线型。释放的速度与所包裹的硫铵量关系不大；发泡时水的比例越高，释放速度越快；颗粒越大，释放越慢；树皮的比例越高，释放越慢。对包膜材料的生物降解性方面的初步实验结果表明：该材料在土壤中能够自然降解。 The biodegradable polyurethane foam was synthesized from the bark, and the controlled release properties of the commonly used nitrogenous fertilizer as ammonium sulfate were investigated. The results show that the porous polyurethane coated with water as a blowing agent after the coating of ammonium sulfate, in the simulation of natural rain, the release curve is roughly parabolic. The rate of release is not related to the amount of ammonium sulfate encapsulated; the higher the proportion of water in the bubble, the faster the release; the larger the particle, the slower the release; the higher the proportion of bark, the slower the release. Preliminary experimental results on the biodegradability of the coating material show that the material can naturally degrade in the soil.